Electronic circuitry and systems sometimes use a high speed link to facilitate communication between two circuits or subsystems. The link, which might be a serial link, may communicate information or data with encoding added by a transmitter that may indicate word-boundaries, distinguish data and control information, scramble the data to spread out electromagnetic interference (EMI), avoid long run-lengths, and balance the number of zeros and ones to avoid a DC imbalance (a lack of DC balance). Examples of encoding schemes include 8b10b, 64/66, and 64/67, which are well known to persons of ordinary skill in the art. Such encoding schemes may be used with a variety of physical layer arrangements, such as pulse amplitude modulation (e.g., PAM-4 and PAM-8) schemes, known to persons of ordinary skill in the art.
At the receiver, the data communicated via the link are processed to determine word boundary, obtain lock with the transmitter, decode, etc. Once word lock is found, the data transitions are used to confirm that word-lock is maintained. The details of those operations are well known to persons of ordinary skill in the art.